Why the light source effects color


Color provides an emotional impact and is sometimes synonymous with a brand. Having the precise color match for your product is a quality that consumers will rely on and expect. However, different light sources can adjust the perceived color of polymers and resins, which you need to take into consideration when manufacturing and displaying your products.

Molecular Structure

The polymer’s molecular structure dictates how it processes light emissions. For example, crystalline resins have a semi-opaque look because of the mixture of their ordered and disordered domains. These characteristics cause the crystalline resins like PP to bend light differently. In comparison, non-crystalline resins are usually comprised of disordered domains, so this causes the light to pass straight through them, causing their transparency.

Melting Points

Another characteristic that has a significant impact on how much light influences a particular resin is its melting points. For example, crystalline resins have a high melting point, requiring much more heat before they alter in appearance. To maintain their appearance, inorganic pigments or other materials may be used that provide stability even at higher temperatures.  Not using heat-stable materials can cause there to be light and dark streaks in the resin.

Chemical Makeup

When polymers contain cross-linked rubber particles, their appearance may be whiter in appearance.  This is the case with such polymers as acrylic, HIPS and ABS. Rubber alters the way that light passes through the resin once it is toughened. If two different color coatings have the same chemical composition, they will match under any light source.
Refractive Index

Another component that affects the color of the resin based on the light source is the angle at which the light bends as it passes through the polymer. Resins that have a combination of different refractive indices can be mixed together, which causes the light to not have a single path to go through. This causes the resin to have a more opaque quality to it.

Energy Distribution

Color changes as it is observed under two different light sources when they have different energy distributions. Even if the resin appears to be the same color due to the same refractive index, the color will be observed differently if the energy distribution is different between the two samples due to a different light source.

Color Matching Tips

Because each light source can affect the color of a polymer, it is important for you to specify the light source in which you plan the resin to be viewed. This will help ensure precise color matching. Here are a few tips to ensure your color will match and that you are satisfied with your experience:

  • Specify if you need a color match with more than one light source.
  • Ask about any additional costs associated with manufacturing a polymer with different colorants due to varying light sources
  • Consider the color match’s tolerance under different light sources
  • Specify the type of spectrophotometer that you wish to use as this tool will help provide the basis for the color match.